As a conventional VCSEL element, a VCSEL element including a plurality of semiconductor layers including an active layer between upper and lower multilayer reflecting mirrors, i.e., distributed Bragg reflector (DBR) mirrors, is disclosed (see, for example, U.S. Pat. No. 6,916,672 and U.S. Pat. No. 6,750,071). Each of VCSEL elements disclosed in U.S. Pat. No. 6,916,672 and U.S. Pat. No. 6,750,071 has a mesa post structure and includes a current confinement layer to confine a current path and to improve current injection efficiency. The current confinement layer has a current blocking portion of Al2O3 positioned at the outer circumference and a circular current injection portion of AlAs positioned at the center of the current blocking portion. The current injection portion serves as a current path when a current is injected into the VCSEL element and an aperture from which a laser light is emitted.
Each of the VCSEL elements disclosed in U.S. Pat. No. 6,916,672 and U.S. Pat. No. 6,750,071 includes a contact layer of a p+-type semiconductor having an increased p-type doping concentration with low resistance at a predetermined position of an uppermost layer of the semiconductor layers to improve current injection efficiency from a p-side annular electrode. The current injected from the p-side annular electrode is efficiently injected into the active layer via the current confinement layer, using the contact layer as the current path. As a result, an oscillation threshold current of the VCSEL element decreases.